JP2019218968A - Control device for magnetic bearing and control method of magnetic bearing - Google Patents

Abstract

To provide a control device for a magnetic bearing and a control method of a magnetic bearing each of which allows for suppression of vibration of a rotor on an auxiliary bearing and repeated mutual contact and separation of the rotor and the auxiliary bearing upon starting of levitation of the rotor.SOLUTION: There is provided a control device for a magnetic bearing of a magnetically levitated motor comprising a rotor, a pair of electromagnets levitating the rotor by electromagnetic force, an auxiliary bearing supporting a rotating shaft of the rotor upon stopping the rotor, and a rotor position detector detecting a levitating direction position of the rotor. The control device comprises an operation current generation part generating an operation electric current value according to deviation between a position command value and a rotor position detected by the rotor position detector, the operation current generation part applies a prescribed initial value more than 0 to the operation current value upon starting of the levitation for positioning the rotor on the prescribed target position from a state in which the rotating shaft of the rotor is supported by the auxiliary bearing.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a magnetic bearing control device and a magnetic bearing control method for a magnetic levitation motor.

  2. Description of the Related Art There is known a magnetic levitation motor provided with a magnetic bearing that uses an electromagnet as a bearing for a rotor of an electric motor and rotates the rotor while floating in the air. Such a magnetic levitation motor includes, for example, a rotor having a rotation axis arranged in a horizontal direction, a pair of electromagnets arranged above and below the rotor, and levitation of the rotor by electromagnetic force, and supporting the rotor when the rotor is stopped. An auxiliary bearing, a rotor position detector for detecting the vertical position of the rotor, and a magnetic bearing control device for controlling the floating position of the rotor.

  The magnetic bearing control device performs feedback control such as PID control in controlling the flying position of the rotor. That is, the magnetic bearing control device energizes the rotor with a current determined by an operation current determined by a deviation between the position command value and the rotor position detected by the rotor position detector and a current determined by a predetermined bias current. are doing.

  Conventionally, when the rotor is lifted from the state where the rotor is supported by the auxiliary bearings (when the rotor is not levitating) and floats to a predetermined target position (the steady position of the rotor), a ramp-shaped position command value is conventionally used. Is input. That is, when the position of the rotor stopped on the auxiliary bearing (the initial position of the rotor) is set to 0 at the start of the ascent, a position command value that increases proportionally from 0 to the target position (that is, the initial value in this case) Is input to the magnetic bearing control device.

JP 2013-79678 A

  In such conventional control at the start of levitation, it takes time until the rotor separates from the auxiliary bearing after the energization of the electromagnet is started, during which time excessive vibration occurs in the rotor, And the auxiliary bearing collide multiple times. When the vibration of the rotor or the collision between the rotor and the auxiliary bearing occurs, noise may be generated or the auxiliary bearing may be damaged.

  As another control mode at the time of starting the floating of the rotor, for example, there is one described in Patent Document 1 described above. In the control mode disclosed in Patent Document 1, the target position is set in stages in order to levitate the rotor to the target position (reference position) (once between the position supported by the auxiliary bearing and the final target position, once). Stop) control. According to this, it is possible to prevent an overshoot in which the rotor rapidly rises by moving the rotor to the target position at one time and collides with the upper auxiliary bearing beyond the target position.

  However, even in the control mode described in Patent Document 1, the above-described problems such as vibrations that occur until the rotor separates from the auxiliary bearing cannot be solved.

  The present invention has been made in view of the above problems, and at the time of starting the floating of the rotor, the rotor vibrates on the auxiliary bearing, and can suppress the repetition of separation and contact, and a magnetic bearing control device and It is an object to provide a magnetic bearing control method.

  A magnetic bearing control device according to one aspect of the present invention includes a rotor, a pair of electromagnets that levitate the rotor by electromagnetic force, an auxiliary bearing that supports a rotating shaft of the rotor when the rotor is not levitated, A magnetic bearing control device for a magnetic levitation motor, comprising: a rotor position detector for detecting a position in a levitation direction; and an operation current corresponding to a deviation between a position command value and a rotor position detected by the rotor position detector. An operating current generating unit that generates a value, wherein the operating current generating unit is configured to start the floating operation for positioning the rotor at a predetermined target position from a state in which the rotation shaft of the rotor is supported by the auxiliary bearing. , A predetermined initial value larger than 0 is given to the operation current value.

  According to the above configuration, when the rotor starts to float, the operation current value at the initial position of the rotor supported by the auxiliary bearing becomes a predetermined initial value larger than zero. Therefore, the operating current rises sharply (increases), and an electromagnetic force required for the rotor to move away from the auxiliary bearing is generated. This makes it possible to suppress the rotor from oscillating rapidly on the auxiliary bearings and repeating the separation and contact when the rotor starts to float.

  The operating current generating unit may be configured to include an initial value adding unit that adds the initial value to a value based on the deviation between the position command value and the rotor position. Alternatively, the operating current generator may include an integrator that integrates the deviation between the position command value and the rotor position, and the predetermined initial value greater than 0 may be set as an initial value of the integrator. . In this case, when the rotor starts to float, the operating current value rises directly and steeply regardless of the position command value. Therefore, it is possible to easily generate an operation current value such that a current that generates an electromagnetic force necessary for separating the rotor from the auxiliary bearing rises sharply without changing the position command value.

  The operation current generation unit may be configured to generate the operation current value using the position command value having a waveform in which a step input waveform is superimposed on a ramp input waveform at the start of the ascent. In this case, when the rotor starts to float, the position command value rises in a step-like manner, so that the resulting operation current value rises indirectly and sharply. Therefore, it is possible to easily generate an operation current value such that a current that generates an electromagnetic force required for separating the rotor from the auxiliary bearing rises sharply only by changing the position command value.

  A magnetic bearing control method according to another aspect of the present invention includes a rotor, a pair of electromagnets that levitate the rotor by electromagnetic force, an auxiliary bearing that supports a rotating shaft of the rotor when the rotor is stopped, A rotor position detector for detecting the position in the predetermined direction, comprising: a magnetic bearing control method for a magnetic levitation motor, comprising: an operation corresponding to a deviation between a position command value and a rotor position detected by the rotor position detector. Generating a current value, wherein the operation current value is greater than 0 at a start of floating for positioning the rotor at a predetermined target position from a state in which the rotation shaft of the rotor is supported by the auxiliary bearing. A predetermined initial value is given.

  According to the above method, the operation current value at the initial position of the rotor supported by the auxiliary bearing becomes a predetermined initial value larger than 0 when the rotor starts to float. Therefore, the operating current rises sharply (increases), and an electromagnetic force required for the rotor to move away from the auxiliary bearing is generated. This makes it possible to suppress the rotor from oscillating rapidly on the auxiliary bearings and repeating the separation and contact when the rotor starts to float.

  According to the present invention, it is possible to suppress the rotor from vibrating on the auxiliary bearing and repeating the separation and the contact when the rotor starts to float.

FIG. 1 is a block diagram showing a schematic configuration of a magnetic levitation motor system to which a magnetic bearing control device according to Embodiment 1 of the present invention is applied. FIG. 2 is a diagram showing a control block in an operation current generation unit of the magnetic bearing control device shown in FIG. FIG. 3 is a graph showing a position command value waveform, an operating current value waveform, and a rotor position waveform at the start of ascent in the first embodiment. FIG. 4 is a diagram illustrating a control block in an operation current generation unit of a magnetic bearing control device according to Embodiment 2 of the present invention. FIG. 5 is a graph showing a position command value waveform, an operating current value waveform, and a rotor position waveform at the start of ascent according to the second embodiment. FIG. 6 is a diagram illustrating a control block in an operation current generation unit of a magnetic bearing control device according to a modification of the embodiment of the present invention. FIG. 7 is a diagram showing a schematic configuration of a magnetic levitation motor according to a modification of the embodiment of the present invention. FIG. 8 is a graph showing the position command value waveform, the operating current value waveform, and the rotor position waveform at the start of ascent in the comparative example.

  Hereinafter, embodiments for implementing the present invention will be described in detail with reference to the drawings. In the following, the same or corresponding elements are denoted by the same reference symbols throughout the drawings, and redundant description will be omitted.

[Embodiment 1]
FIG. 1 is a block diagram showing a schematic configuration of a magnetic levitation motor system to which a magnetic bearing control device according to Embodiment 1 of the present invention is applied. The magnetic levitation motor system 1 is used as a blower for aeration used in a water treatment system or the like. In the present embodiment, the magnetic levitation motor system 1 includes a magnetic levitation motor 2 and a magnetic bearing control device 3.

  The magnetic levitation motor 2 includes a rotor 5, a stator 6, and a pair of magnetic bearing mechanisms 7a and 7b. The rotor 5 includes a rotating shaft 4 extending in the horizontal direction, a rotor main body 8 fixed to the rotating shaft 4, and a pair of bearing corresponding portions 9 a and 9 b fixed to the rotating shaft 4 on both axial sides of the rotor main body 8. It has. In the rotor 5, these components 4, 8, 9 a, 9 b rotate around the rotation shaft 4 integrally.

  The pair of magnetic bearing mechanisms 7a, 7b include electromagnet pairs 10a, 10b arranged corresponding to the pair of bearing corresponding parts 9a, 9b. Each electromagnet pair 10a, 10b includes a pair of electromagnets (upper electromagnet 11 and lower electromagnet 12) arranged above and below the rotation shaft 4 of the rotor 5, respectively. Further, the pair of magnetic bearing mechanisms 7a and 7b respectively detect auxiliary bearings 13a and 13b for preventing the position of the rotary shaft 4 of the rotor 5 from deviating, and detect the floating position (vertical position) of the rotor 5. And rotor position detectors 14a and 14b. The rotor position detectors 14a and 14b are configured by, for example, a rotary encoder or the like.

  The auxiliary bearings 13a and 13b include an upper auxiliary bearing 15 and a lower auxiliary bearing 16, respectively. The lower auxiliary bearings 16 of the auxiliary bearings 13a and 13b support the rotating shaft 4 of the rotor 5 when the rotor 5 is stopped (indicated by imaginary lines in FIG. 1). The vertical position (axial position of the rotary shaft 4 in FIG. 1) of the rotor 5 in a state (stopped state) supported by the lower auxiliary bearing 16 is set to 0.

  The magnetic bearing control device 3 includes a first magnetic bearing control device 3a that controls the first magnetic bearing mechanism 7a and a second magnetic bearing control device 3b that controls the second magnetic bearing mechanism 7b. Have. The magnetic bearing control devices 3a and 3b generate operation current values Ima and Imb according to the deviation between the position command values Pca and Pcb and the rotor positions Pa and Pb detected by the rotor position detectors 14a and 14b, respectively. An operation current generator 17 is provided.

  Each of the magnetic bearing control devices 3a and 3b includes upper currents Ima1 and Imb1 that flow to the corresponding upper electromagnet 11 and lower currents Ima2 that flow to the lower electromagnet 12 from the operation current values Ima and Imb generated by the operation current generation unit 17, respectively. Imb2 is generated and output to the upper electromagnet 11 and the lower electromagnet 12. When a current flows through the upper electromagnet 11 and the lower electromagnet 12, an electromagnetic force is generated in the electromagnet pairs 10a and 10b, and the rotor 5 floats. Each magnetic bearing control device 3a, 3b generates the operating current values Ima, Imb so that the rotor positions Pa, Pb detected by the rotor position detectors 14a, 14b match the position command values Pca, Pcb. 5 is performed.

  After the rotor 5 floats, the drive control device (not shown) controls the rotation of the rotor 5. The magnetic bearing control device 3 (3a, 3b) may be realized by the same control device as the drive control device, or may be configured separately from the drive control device. In addition, the first magnetic bearing control device 3a and the second magnetic bearing control device 3b may be configured by one control device (computer such as a microcontroller) or may be configured by individual (two) control devices. May be done.

  Here, each of the magnetic bearing control devices 3a and 3b moves the rotor 5 to a predetermined target position (the position of the rotor 5) from a state where the rotating shaft 4 of the rotor 5 is supported by the auxiliary bearings 13a and 13b (lower auxiliary bearing 16). At the start of levitation for positioning at the position (steady rotation position) Pt, levitation start control is performed. In the levitation start control, each of the magnetic bearing controllers 3a and 3b is configured to give a predetermined initial value larger than 0 to the operation current value.

  The initial value is set, for example, based on the maximum value of the operation current (the maximum value in the graph (b) of FIG. 8) required to control the position of the rotor 5 at the same target position Pt in the conventional configuration.

  FIG. 2 is a diagram showing a control block in an operation current generation unit of the magnetic bearing control device shown in FIG. In FIG. 2 and the following description, the operation current generation unit 17 in the first magnetic bearing control device 3a is mainly described, but the operation current generation unit 17 in the second magnetic bearing control device 3b also has the same configuration.

  As shown in FIG. 2, the operation current generation unit 17 in the present embodiment is configured to give an initial value to the operation current value output when the rotor 5 starts floating. More specifically, the operation current generation unit 17 includes a PID control unit 18 for performing PID control on a deviation ΔPa between the position command value Pca and the rotor position Pa, and an operation current value generated at the start of ascent. An initial value adding unit 19 that adds an initial value Iin to Ima to generate an operation current value Imca. Further, each of the magnetic bearing control devices 3a and 3b generates an upper current Ima1 output to the upper electromagnet 11 and a lower current Ima2 output to the lower electromagnet 12 from the operation current value Imca output from the operation current generation unit 17. A current output unit 20 is provided.

  The PID control unit 18 includes a subtractor 21, a proportional operation unit 22, an integral operation unit 23, a differential operation unit 24, and an adder 25. The subtractor 21 obtains the deviation ΔPa by subtracting the rotor position Pa from the position command value Pca. The proportional operation unit 22 performs a proportional operation by multiplying the deviation ΔPa by a predetermined gain Kp. The integral operation unit 23 performs an integral operation by multiplying the deviation ΔPa by a predetermined gain Ki. The differential operation unit 24 performs a differential operation by multiplying the deviation ΔPa by a predetermined gain Kd. The adder 25 generates an operation current value (base value) Ima by adding the outputs of the arithmetic units 22 to 24.

  The current output unit 20 outputs a current value obtained by adding an operation current value (an output of an initial value adding unit 19 described later) Imca to a predetermined bias current value Iba as an upper current Ima1, and performs an operation from the predetermined bias current value Iba. The current value obtained by subtracting the current value Imca is output as the lower current Ima2. In this manner, the current output unit 20 generates the upper current Ima1 flowing to the upper electromagnet 11 and the lower current Ima2 flowing to the lower electromagnet 12 from one operation current value Imca.

  The operation current value Ima output from the PID control unit 18 is input to the initial value addition unit 19. The initial value adding unit 19 adds the initial value Iin to the output (operation current value Ima) of the PID control unit 18 at the time of the start of ascent, and generates the corrected operation current value Imca at the start of the ascent. FIG. 3 shows a position command value waveform indicating a temporal change of the position command value at the start of ascent, a control current value waveform indicating a temporal change of the control current value, and a temporal change of the rotor position in the first embodiment. It is a graph which shows a rotor position waveform. FIG. 8 is a graph showing a position command value waveform, an operating current value waveform, and a rotor position waveform at the start of ascent in the comparative example. In each figure, the graph (a) shows the position command value waveform, the graph (b) shows the operation current value waveform, and the graph (c) shows the rotor position waveform. FIGS. 3 and 8 show graphs of each value in the first magnetic bearing control device 3a.

  Position command value Pca in the present embodiment and position command value Pca in the comparative example have the same waveform. In other words, the position command value Pca is determined such that the rotor 5 starts to float by passing a current through the electromagnet pair 10a of the first magnetic bearing mechanism 7a at time t1, and the rotor 5 on the first magnetic bearing mechanism 7a side at time t2. It has such a waveform that the ascent is completed (it reaches a predetermined target position Pt). Therefore, the position command value Pca rises like a ramp from time t1 to time t2 (linearly rises with time). The position command value Pca at time t1 is 0.

  In this case, as shown in FIG. 8, in the conventional configuration, the operation current value Ima generated according to the position command value Pca that increases in a ramp shape from time t1 gradually increases from zero. For this reason, as shown in the graph (c) of FIG. 8, the actual rotor position vibrates on the lower auxiliary bearing 16 for a while (period tx) or the lower auxiliary bearing does not completely float. 16 again.

  On the other hand, according to the present embodiment, as shown in FIG. 3, at time t1 when the rotor 5 starts to float, the operation current value Imca is set to 0 even though the position command value Pca is 0. A large predetermined initial value Iin is output. Therefore, the operating current rises sharply (increases), and an electromagnetic force necessary for moving the rotor 5 away from the auxiliary bearing 13a (the lower bearing 16) is generated. Therefore, the rotor 5 quickly rises, and as shown in the graph (c) of FIG. 3, the actual rotor position Pa also rises in a ramp shape following the position command value Pca. As described above, according to the present embodiment, it is possible to prevent the rotor 5 from vibrating on the auxiliary bearings 13a and 13b and repeating the separation and the contact when the rotor 5 starts to float.

  In particular, in the present embodiment, when the rotor 5 starts to float, the initial value Iin is added to the operation current value Ima generated by the PID control unit 18. As a result, a current that generates an electromagnetic force necessary for the rotor 5 to move away from the auxiliary bearing 13a (operation current value) by simply performing an operation of adding the initial value Iin to the output of the operation current value Ima in the existing magnetic bearing control device. Imca) rises steeply directly. Therefore, it is possible to easily generate the operation current value Imca such that the current required to separate the rotor 5 from the auxiliary bearing 13a rises sharply without changing the position command value Pca.

  In the present embodiment, the second magnetic bearing control device 3b starts floating of the rotor 5 on the second magnetic bearing mechanism 7b side after the rotor 5 has floated to the target position Pt on the first magnetic bearing mechanism 7a side. Next, the second magnetic bearing mechanism 7b is controlled. In the examples of FIGS. 3 and 8, the rotor 5 starts to float on the second magnetic bearing mechanism 7b side at time t3 (current is flowing through the electromagnet pair 10b). Even in such a case, the second magnetic bearing control device 3b performs control to add the initial value Iin to the operation current value Ima generated by the PID control unit 18, as in the first magnetic bearing control device 3a.

  In the conventional configuration, similarly to the behavior on the first magnetic bearing mechanism 7a side, the rotor 5 vibrates on the auxiliary bearing 13b at the start of the levitation control of the rotor 5 on the second magnetic bearing mechanism 7b side. Vibrate. In the graph (c) of FIG. 8, the reason why the graph vibrates after the time t3 is that the vibration of the rotor 5 in the second magnetic bearing mechanism 7b is transmitted to the first magnetic bearing mechanism 7a and exerts an influence. It is shown that. Accordingly, the operation current value Ima output from the first magnetic bearing control device 3a also largely fluctuates up and down in an attempt to maintain the position of the rotor 5 on the first magnetic bearing mechanism 7a side at the target position.

  On the other hand, according to the present embodiment, the operation current value Imca output from the operation current generation unit 17 of the second magnetic bearing control device 3b is the operation current value even though the position command value Pca is 0. A predetermined initial value Iin larger than 0 is output as Imca. Therefore, a current that generates an electromagnetic force necessary for the rotor 5 to separate from the auxiliary bearing 13b rises sharply. Therefore, the actual rotor position Pb also rises in a ramp shape following the position command value Pcb. Therefore, as shown in the graph (c) of FIG. 3, when the second magnetic bearing mechanism 7b starts floating at time t3, the fluctuation of the rotor position Pa on the first magnetic bearing mechanism 7a side is suppressed. Further, as shown in the graph (b) of FIG. 3, the operation current value Imca output from the first magnetic bearing control device 3a hardly changes. This makes it possible to control the rotor position when the rotor 5 starts to levitate with high accuracy, and to prevent the rotor 5 from being damaged.

[Embodiment 2]
Next, a second embodiment of the present invention will be described. FIG. 4 is a diagram illustrating a control block in an operation current generation unit of a magnetic bearing control device according to Embodiment 2 of the present invention. In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted. The magnetic bearing control device 3B of the present embodiment is different from that of the first embodiment in that the operation current generator 17B uses a position command value having a waveform in which a step input waveform is superimposed on a ramp input waveform at the start of levitation. To generate the operation current value.

  More specifically, the operation current generation unit 17B adds a step-like initial value Pin to the ramp-shaped position command value Pca at the time of the start of ascent, and generates a corrected position command value Pcca at the start of the ascent. An initial value adder 19B is provided. In the present embodiment, initial value adding section 19B outputs a value obtained by multiplying a value obtained by adding initial value Pin to position command value Pca by a predetermined gain, as corrected position command value Pcca. Thereby, the magnitude of the position command value corresponding to the target position Pt in the corrected position command value Pcca is adjusted to be the same as the original position command value Pca. Other configurations are the same as those of the magnetic levitation motor system 1 shown in FIG.

  FIG. 5 is a graph showing a position command value waveform, an operating current value waveform, and a rotor position waveform at the start of ascent according to the second embodiment. The graph (a) in FIG. 5 shows the waveform of the corrected position command value Pcca. The waveform of the position command value Pca before correction is the same waveform as the graph (a) in FIG.

  As shown in the graph (a) of FIG. 5, the corrected position command value Pcca is obtained by performing a gain process on the initial value component Pin ′ (the step-like initial value Pin input to the initial value adding unit 19B) at time t1. Value). As a result, as shown in the graph (b) of FIG. 5, the operation current value Ima rises sharply from the time t1, and becomes almost the same value as the initial value Iin of the operation current value in the graph (b) of FIG. As a result, as shown in the graph (c) of FIG. 5, the rotor position Pa rises immediately after the time t1 (the rotor 5 floats immediately after the time t1).

  As described above, according to the present embodiment, when the rotor 5 starts to float, the corrected position command value Pcca rises stepwise, and the resulting operation current value Ima rises indirectly sharply. . Therefore, an operation current value Ima at which a current for generating an electromagnetic force required for separating the rotor 5 from the lower auxiliary bearing 16 of the auxiliary bearings 13a and 13b rises sharply is obtained by adding the initial value Pin to the position command value Pca. It can be easily generated simply by changing to the corrected position command value Pcca.

[Modification]
As described above, the embodiments of the present invention have been described, but the present invention is not limited to the above embodiments, and various improvements, changes, and modifications can be made without departing from the gist of the present invention.

  For example, the generation mode of the operation current values Ima, Imb or Imca, Imbc is not limited to the above-described embodiment as long as a predetermined initial value larger than 0 is given to the operation current values Ima, Imb at the start of floating of the rotor 5. . Note that “greater than 0” is a significant value that cannot be obtained with an operation current value in which the magnitude of the operation current value in the direction in which the rotor 5 floats in the current flowing through the electromagnet pair 10a, 10b increases from 0 to a ramp shape. This means that the operation current values Ima, Imb or Imca, Imbc itself are not limited to positive values, but may include negative values.

  Further, in the above embodiment, after the first magnetic bearing control device 3a controls the levitation of the rotor 5 on the first magnetic bearing mechanism 7a side, the second magnetic bearing control device 3b controls the second magnetic bearing mechanism 7b side. Although the aspect in which the levitation control of the rotor 5 is performed is described above, the levitation control of the rotor 5 may be started simultaneously for both the first magnetic bearing mechanism 7a and the second magnetic bearing mechanism 7b. In this case, the magnetic bearing control device 3 may include only the first magnetic bearing control device 3a. That is, the upper current Ima1 and the lower current Ima2 output from the first magnetic bearing control device 3a may be configured to flow to both (the upper electromagnet 11 and the lower electromagnet 12 in) the pair of electromagnets 10a and 10b.

  Further, in the above-described embodiment, an example has been described in which the upper currents Ima1 and Imb1 and the lower currents Ima2 and Imb2 are generated from one operation current value Imca, Ima, Imcb, and Imb. Alternatively, the operating current values for the upper currents Ima1 and Imb1 and the operating current values for the lower currents Ima2 and Imb2 may be individually generated.

  In the first embodiment, the initial value addition unit 19 adds the initial value Iin to the output (operation current value Ima) of the PID control unit 18 at the time of the start of ascent, and the corrected operating current at the start of the ascent. The embodiment for generating the value Imca has been described. Instead, the initial value adder 19 adds the initial value Iin to, for example, the output of the integration calculator 23 before adding the outputs of the calculators 22 to 24 to the adder 25 in the PID controller 18. May be configured. That is, the initial value adding unit 19 is configured to add the initial value Iin to a value based on the deviation ΔPa between the position command value Pca and the rotor position Pa (including at least the output of the integration operation unit 23 and the operation current value Ima). It should just be done.

  Further, a predetermined initial value larger than 0 may be set as the initial value of the integrator 23 of the PID control unit 18. FIG. 6 is a diagram illustrating a control block in an operation current generation unit of a magnetic bearing control device according to a modification of the embodiment of the present invention. The operation current generation unit 17C of the magnetic bearing control device 3C shown in FIG. 6 replaces the initial value addition unit 19 (FIG. 2) in the first embodiment with an initial value that gives the integrator 23 of the PID control unit 18C an initial value Ci. A value setting unit 26 is provided. In this case, the output of the integrator 23 at the start of the levitation control of the rotor 5 becomes the initial value regardless of the deviation ΔPa between the position command value Pca and the rotor position Pa.

  Further, in the second embodiment, the initial value adding unit 19B of the operation current generating unit 17B adds the step-shaped initial value Pin to the ramp-shaped position command value Pca at the time of the start of flying, and performs correction at the time of the start of flying. The manner in which the subsequent position command value Pcca is generated has been described. Instead of this, the position command values Pca and Pcb themselves may be configured to be input to the magnetic bearing control devices 3a and 3b as waveforms in which the step input waveform is superimposed on the ramp input waveform.

  Also, in the above-described embodiment, an example has been described in which the operation current generation units 17 and 17B include the PID control unit 18. However, instead of the PID control unit 18, a PI control unit that performs PI control or a proportional control that performs proportional control is performed. You may have a control part.

  Further, in the above embodiment, the description has been given based on the configuration in which the rotating shaft 4 of the rotor 5 extends in the horizontal direction and the pair of electromagnets 11 and 12 are respectively arranged in the vertical direction of the rotating shaft 4. The extending direction of the rotating shaft 4 may be other than the horizontal direction. For example, as shown in FIG. 7, the present control mode can be applied to a shaft levitation motor 2 </ b> B in which the rotating shaft 4 of the rotor 5 extends in the vertical direction and the rotor 5 floats in the direction of the rotating shaft 4. In the example of FIG. 7, the pair of electromagnets 11 </ b> B and 12 </ b> B are arranged on the first surface side (electromagnet 11 </ b> B) that faces downward in the axial direction of the disk-shaped bearing corresponding portion 9 provided on the rotating shaft 4 and the shaft of the bearing corresponding portion 9. It is provided on the second surface side (electromagnet 12B) facing upward in the direction. In the example of FIG. 7, the bearing corresponding portion 9, the pair of electromagnets 11B and 12B, and the auxiliary bearings 15 and 16 are provided only below the rotor body 8, and the rotor position detector 14 is provided above the rotor body 8. Although only an example is shown, similar to the configuration in FIG. 1, these configurations may be provided on both sides of the rotor main body 8.

  Thus, regardless of the floating direction of the rotor, a pair of electromagnets that levitate the rotor by electromagnetic force, auxiliary bearings that support the rotating shaft of the rotor when the rotor is stopped, and rotor position detection that detects the position of the rotor in the floating direction This control mode can be applied to a magnetic levitation motor including a motor.

  INDUSTRIAL APPLICABILITY The present invention is useful for providing a magnetic bearing control device and a magnetic bearing control method that can prevent the rotor from vibrating on the auxiliary bearing and repeating repetition of separation and contact when the rotor starts to float. It is.

2 Magnetic levitation motors 3, 3a, 3b, 3B Magnetic bearing control device 4 Rotary shaft 5 Rotor 11, 12 A pair of electromagnets 13a, 13b Auxiliary bearings 14a, 14b Rotor position detector 17 Operating current generator 18 PID controller 19 Initial value Adder

Claims (5)

A rotor, a pair of electromagnets that levitate the rotor by electromagnetic force, an auxiliary bearing that supports a rotating shaft of the rotor when the rotor is not levitated, and a rotor position detector that detects a position in the floating direction of the rotor. A magnetic bearing control device for a magnetic levitation motor comprising:
An operation current generator that generates an operation current value according to a deviation between a position command value and a rotor position detected by the rotor position detector,
The operating current generating unit is configured such that, at the time of start of floating for positioning the rotor at a predetermined target position from a state in which the rotation shaft of the rotor is supported by the auxiliary bearing, a predetermined value larger than 0 is set to the operating current value. A magnetic bearing controller configured to provide an initial value.   2. The magnetic bearing control according to claim 1, wherein the operation current generator includes an initial value adder that adds the initial value to a value based on the deviation between the position command value and the rotor position. 3. apparatus. The operating current generator includes an integrator that integrates the deviation between the position command value and the rotor position,
The magnetic bearing control device according to claim 1, wherein the predetermined initial value larger than 0 is set as an initial value of the integrator.   2. The operation current generator according to claim 1, wherein the operation current generator is configured to generate the operation current value using the position command value having a waveform in which a step input waveform is superimposed on a ramp input waveform at the start of the ascent. 3. The magnetic bearing control device as described in the above. A rotor, a pair of electromagnets that levitate the rotor by electromagnetic force, an auxiliary bearing that supports a rotating shaft of the rotor when the rotor is not levitated, and a rotor position detector that detects a position in the floating direction of the rotor. A magnetic bearing control method for a magnetic levitation motor comprising:
Including a step of generating an operation current value according to a deviation between a position command value and a rotor position detected by the rotor position detector,
A magnetic bearing for giving a predetermined initial value greater than 0 to the operation current value at the time of starting levitation for positioning the rotor at a predetermined target position from a state in which the rotation shaft of the rotor is supported by the auxiliary bearing; Control method.

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